“Client terminal” refers to a device of a local network, configured to be connected to an access network by a set of connections of the copper, optical and/or radio type. The client terminal can be an individual terminal, dedicated to a user, or a group terminal, shared between several users.
“Access network” refers to a network providing multiplexing and connectivity between a local network and one or more service networks, possibly via one or more gathering networks. “Operator terminal” refers to a device of the access network.
Finally, the expression “placement on standby policy” refers to a set of rules relating to the conditions in which a placement on standby can be applied and/or to the type or types of standby to be applied. The placement on standby policy depends on the type of client terminal, for example individual or group, on a predetermined configuration of the client terminal and/or on services configured for the client terminal.
For example, the conditions in which a placement on standby can be applied are not the same in the presence of a limited availability service and in presence of a high availability service. In fact, a limited availability service is a service for which a power off corresponds to a switching off of the power supply of the client terminal and consequently to a switching off of the service. A limited availability service is a service for which a break in the service has little effect on the quality of experience. On the contrary, a high availability service is a service necessitating a high level of availability, for example a service of the intrusion detection, health monitoring, backup lines, etc. type. For such a high availability service, a break in service is harmful to the quality of experience.
Telecommunication operators deploy client terminals, in particular modems, in order to provide uses with an increasingly wide band connectivity allowing the multiplexing of services on a single medium.
The transmission technologies used are numerous, as are the types of networks. Each type of transmission technology and each type of network has its own constraints. Moreover, the configurations of gathering and service networks are chosen by the service operators and the configurations of the local networks are chosen by the users.
It is the responsibility of the access network operator, i.e. the telecommunication operator, to identify the best compromises making it possible to achieve energy saving whilst taking care of everyone's choices. In particular, it is the responsibility of the access network operator to identify conditions in which a placement on standby can be applied without being felt in a negative manner by the final user, in order to achieve energy saving without degrading the quality of service. It should be noted that, although the energy savings on each element are small on approaching the periphery of the network, the total saving becomes dominant because of the large number of terminations.
Several types of standby are known. For example, standby procedures of the PS (Power Shedding) type allow the selective placement on standby of service interfaces so as to extend the service life of a battery of a client terminal. However, standbys of this type have drawbacks. In particular, they require a prioritisation between interfaces, which can be implemented in a hardware manner in the client terminal without monitoring or control by the operator terminal.
Standbys of the “Dozing” type allow the placement on standby of all or part of a transmission chain in the client to network direction when the client does not have useful data to transmit. In this case, the management link between the operator terminal and the client terminal is also cut and the operator terminal cannot therefore determine, during the standby period, if the client terminal has failed and/or if the optical fibre is broken.
Standbys of the “Fast Sleep” or “Cyclic Sleep” type consist in the temporary switching off of the circuitry of the access network interface of the client terminal. The descending and ascending optical transmissions are no longer received during the standby period but are the subject of a protocol exchange defining the characteristics of the standby in order not to confuse standby and poor operation. In order not to have an excessive impact on the operation, a cyclic fast resumption is defined in order to allow the readjustment of the parameters between the operator terminal and the client terminal. The operator terminal must therefore keep active time slots in its frame cycle which allow a fast resumption of exchanges.
Standbys of the “Deep Sleep” type consist in a switching off resulting in a total loss of contact between the operator terminal and the client terminal. Only a physical action on the client terminal and/or a detection of activity on an access network interface then allows the resumption of exchanges.
Each of these types of standby is specifically adapted to a system and/or to a situation, and does not therefore make it possible, in a complex telecommunication network, to optimise the energy saving produced without degrading the quality of service.